1. Technical Field
The present disclosure relates to a data logging apparatus. More specifically, the present disclosure relates to a data logging apparatus that stores communications data transmitted/received between a first apparatus and a second apparatus as log data, determines whether an event occurs based on the communications data, and stores log data within predetermined time periods before and after the time point at which the event has occurred, i.e., between a log start time and a log end time as event data.
2. Description of the Related Art
In typical industrial fields, a variety of industrial installations are monitored and are operated based on the results of the monitoring. When a failure occurs, the industrial installation is repaired and maintained based on the monitoring result.
To this end, industrial installations conduct communications thereamong, and transmit/receive information on the operating status of the industrial installations and instructions necessary for operating them as communications messages in the form of digital data or as I/O (input/output) signals in the form of analog data.
In addition, if an event occurs in the industrial installations such as an error or failure, a message notifying the event (“event occurrence message”) is transmitted to an external apparatus to repair and maintain the industrial installations. In doing so, the industrial installations store only the message notifying the event.
In order to recover the industrial installations from error and failure later on, the communications messages and I/O signals transmitted/received among the industrial installations before and after the error and failure have occurred are analyzed, to derive the cause of the error and failure therefrom.
Existing industrial installations, however, store event occurrence messages only and not communications message and I/O signal. Therefore, there is a problem in that it is difficult to analyze the cause of the error and failure.